Abbreviation of Railroad Retirement Act (RRTA). In Union Pacific Railroad Co. v. United States (No. 16-3574, 8th Circuit, 2017), the court ruled that a railroad could get a refund of the RRTA taxes that it paid on company stock used to compensate employees. Stock compensation is not subject to the RRTA in the same way it is for FICA taxes.

For more details on the decision, including the court's distinction between money and stock compensation, see commentaries from CCH and KPMG.